Conventionally, a coal burning boiler including a furnace which combusts crushed pieces of coal is known. Some of particles of coal combustion ash generated in the furnace of the boiler melt and clump together to form porous masses or lumps (clinker ash), which fall onto the furnace bottom.
As known methods of ash discharge processing for discharging the clinker ash from the furnace bottom of the furnace, there are a submerged conveyor method which continuously discharges the clinker ash by a submerged drag chain conveyor installed at the furnace bottom, and a dry clinker conveyor method which continuously or intermittently discharges the clinker ash by a dry clinker conveyor installed at the furnace bottom (see Patent Literature 1).
For example, a conveyor apparatus disclosed in Patent Literature 1 includes a conveyor belt having a collection area located below a bottom opening of a boiler furnace, and a housing surrounding the conveyor belt. High-temperature material discharged from the boiler furnace falls onto the conveyor belt, and is cooled while being transported by the conveyor belt.